who laughed quite so?

Looking down the garden, he saw them, sitting under a pergola,
half-veiled by the purple drifts of the wistaria that hung in trails
between them and him. Through its twilight screen he saw Denis in a
dinner-jacket, leaning back in a cane chair, his elbow on its arm, a
cigarette in his raised hand, speaking. The light from a big yellow
lantern swinging above them lit his clear profile, gleamed on his fair
hair. Opposite him was Lucy, in a white frock, her elbows on a little
table, her chin in her two hands, her eyes wide and grey and full of the
wonder of the twilight. And beyond her sat Lord Evelyn, leaning back with
closed eyes, a cigar in his delicate white hand.

Peter stood and looked, and a little faint, doubtful smile twitched at
his lips, as at a dear, familiar sight long unseen. Should he approach?
Should he speak? For a moment he hung in doubt.

Then he turned away. He had no part with them, nor they with him. His
part--Rodney had said it once--was to clear out.

Livio, close to him, was twanging his mandolin and singing some absurd
melody:

"Ah, Signor!"
"Scusi, Signora?"
"È forae il mio marito,
Da molti anni smarrito?..."

Peter broke in softly, "Livio, I go. I have had enough."